CHANGES IN COTTON WEED MANAGEMENT PRACTICES FOLLOWING THE DEVELOPMENT OF GLYPHOSATE-RESISTANT PALMER AMARANTH

Abstract The widespread adoption of glyphosate-resistant crops has resulted in significant changes in crop production practices; in cotton, these changes include: increased use of glyphosate and a concomitant decrease in the application of other herbicides (photosystem II inhibitors, dinitroanilines, arsenates, and biosynthesis inhibitors). Following the development of glyphosate-resistant (GR) Palmer amaranth (which may infest up to 50% of the US upland cotton acres), it is reasonable to assume that another shift in weed management practices is already occurring. Understanding grower methods and habits will help us fill gaps in research and extension programs, as well as identify potential areas of abuse and prevent the development of other herbicide resistances.